a part of the cell containing DNA and RNA and responsible for growth and reproduction
any histologically identifiable mass of neural cell bodies in the brain or spinal cord
the positively charged dense center of an atom
(astronomy) the center of the head of a comet; consists of small solid particles of ice and frozen gas that vaporizes on approaching the sun to form the coma and tail
an imaginary line around the Earth forming the great circle that is equidistant from the north and south poles; "the equator is the boundary between the northern and southern hemispheres"
a circle dividing a sphere or other surface into two usually equal and symmetrical parts
a mechanical device in a camera that controls size of aperture of the lens; "the new cameras adjust the diaphragm automatically"
electro-acoustic transducer that vibrates to receive or produce sound waves
a contraceptive device consisting of a flexible dome-shaped cup made of rubber or plastic; it is filled with spermicide and fitted over the uterine cervix
(anatomy) a muscular partition separating the abdominal and thoracic cavities; functions in respiration